Shadow-line device with a structurally independent guideway

ABSTRACT

A device for projecting shadow lines on a work surface, at least certain of these lines being shiftable in response to control system, the movable projector assemblies being mounted on carries supported on a guideway formed by a relatively heavy rail with flange grooves, the rail being supported by the frame of the device so as to leave the rail in relatively stress-free condition.

United States Patent 91 Carter et al.

111 3,729,265 451 Apr. 24, 1973 SHADOW-LINE DEVICE WITH A STRUCTURALLY INDEPENDENT GUIDEWAY Inventors: Andrew G. Carter, 2930 Lake Drive, S.E.; Charles L. Morgan, 1137 Crosby, N.W., both of Grand Rapids, Mich.

Filed: Oct. 8, 1970 Appl. No.: 79,207

US. Cl. ..356/256, 143/168 B Int. Cl. ..B27b 31/06 Field of Search ..356/256; 143/168,

References Cited UNITED STATES PATENTS Grant 143/168 B X Horstkotte ..143/168 13 3,368,597 2/1968 Carter ..143/168 R I FOREIGN PATENTS OR APPLICATIONS France ..16/87.6 Germany ..16/87.6

Primary [hummer-Ronald L. Wibert Assistant.Eraminer-F. L. Evans Attorney-Glenn B. Morse [57] ABSTRACT A device for projecting shadow lines on a work surface, at least certain of these lines being shiftable in response to control system, the movable projector assemblies being mounted on carries supported on a guideway formed by a relatively heavy rail with flange grooves, the rail being supported by the frame of the device so as to leave the rail in relatively stress-free condition.

5 Claims, 12 Drawing Figures Patented April 24, 1973 Q 3,729,265

6 Sheets-Shea; 1

25 v lllq 20 211 1::

a 88 "Elm: I. 22 24 INVENTORS Andrew G. Carter Fig. 2 Charles L. Morgan A TTOR/VE Y Patented April 24, 1973 IN VE/VTO/PS A TTORNE' Y hm mm Qm Nu 5 0m "ll-ll:

Charles L. Morgan 6 Sheets-Sheet 2 Andrew 6. Carter Patented April 24, 197 3 3,729,265

6 Sheets-Sheet 5 I INVENTORS Andrew G. Carter Charles L. Morgan A TTOR/VEY Patented April 24, 1973 3,729,265

6 Sheets-Sheet 5 OOOOOOOOOOOOQOOOOOOOOOO 0000 0 000000000000000 00000000 0000 O OOOO OOOO 5 4| .I 2 1111111 I I Qim 36 7c 5 A w Y n|1|:-.-||r.1 Y 27 ooooooooocoooooooooooooooooo oooooooooooooooooooooooooooo IIVVENTORS Andrew G. Carter Charles L. Morgan ATTORNEY Patented April 24, 1973 I 3,729,265

6 Sheets-Sheet 6 Andrew G. Carter Charles L. Morgan A TTOR/VE Y SHADOW-LINE DEVICE WITH A STRUCTURALLY INDEPENDENT GUIDEWAY BACKGROUND OF THE INVENTION Shadow-line devices are used in conjunction with a number of machines for the purpose of indicating the path that a cut will take through a work piece placed on the feed table of the machine, so that the relative position of the work piece and the cutting devices can be adjusted by the operator. These devices center in projector assemblies that include a light source and a small-diameter wire or line placed within the projection sector of the light source to obstruct enough light to cast a shadow. These projector assemblies are normally mounted on carriers supported on a guideway arranged transversely to the direction of the shadow line. The position of the carriers is normally correlated with the cutting equipment on the machine with which the shadow line device is associated, so that movement of the cutting device induces corresponding movement of the shadow line, thus indicating on the work piece the cutting path that will normally result from the in-feed action of the machine. The lateralpo sitioning of the carriers on the guideway is preferably under control of a cable system, although one or more of the carriers may be left in a fixed position to establish a reference shadow line, or a shadow line corresponding to a fixed cutting element. Applications of this general type are frequently encountered in saw mills, where it is con tinually necessary to feed rough boards slabbed off a log into a machine so that they may be cut to width with a minimum of waste. It is the usual practice to place these boards on the feed table of the machine, and then adjust the placement of the cutting saws accordingly. The shadow line device makes this practice much more accurate, and requires less effort and judgment on the part of an operator. Devices of this type are covered in US. Pat. No. 3,368,597, and in our pending application for US. Pat. Ser. No. 879,730, filed on Nov. 25, 1969.

A continually recurring problem in the design of shadow line devices is the maintenance of the orientation of the shadow lines after this orientation has been established carefully by initial installation. Previous guideway arrangements establishing the orientation and path of movement of the carriers have shown tendencies for inaccuracy to develop as a result of accumulations of manufacturing tolerence and the distortions due to mounting and vibration stresses. Errors in the placement of these assemblies are magnified considerably by the time the shadow line is projected on the working surface, and the effective utilization of the principles in these machines requires that these errors be reduced to an absolute minimum. It should be noted here that irregularities in the guideways will not only induce variations in the position of the carriers directly, but are likely to further induce oscillations in the carrier and projector assemblies as a moving carrier passes over these points of guideway discontinuity. A shadow line oscillating as a result of the vibrations of the components ofthe machine loses much ofits value.

SUMMARY OF THE INVENTION An improved stability is built into a machine embodying the present invention by the provision ofa uni tary rail forming the guideway structure, with this rail being supported against the effect of gravity by the framework of the machine. The structural interrelationship between the rail and the framework of the machine is such that the rail is supported in relatively stress-free condition. The guideway surfaces on the rail can be machined to extreme accuracy, and installation of exterior stresses applied to the frame work of the machine are not transferred to the rail to the point of distorting the relationship of the guideway surfaces.

Preferably, the guideway rail is in the form ofa channel mounted in an open side of the frame-housing of a machine so that the outer edges of the side flanges of the channel are testing against inwardly turned flanges defining the opening in the frame-housing. Control cables responsible for the placement of the carriers along the guideway are preferably arranged with opposite courses of the cables on respectively opposite sides of the web of the rail interconnecting the side flanges. This arrangement makes it possible to develop the most compact form of the assembly, and to utilize the rela tively greater thickness of material of the rail flanges adjacent to the web to accommodate the grooves forming the guideway surfaces.

DESCRIPTION OF THE DRAWINGS FIG. I (Sheet 1) is a perspective view of a machine embodying the invention.

FIG. 2 (Sheet 1) is a'perspective view of the machine shown in FIG. 1, from the opposite side from that shown in FIG. 1.

FIG. 3 (Sheet 2) is an elevation of the side of the machine shown in FIG. 2, on an enlarged scale, with the floorsupport structure removed.

FIG. 4 (Sheet 2) is a sectional elevation the plane 4-4 of FIG. 5.

FIG. 5 (Sheet 3) is a sectional plan on the plane 5-5 of FIG. 4.

FIG. 6 (Sheet 4) is a bottom view of the machine, with portions of the projector assemblies broken away to show the carriers.

FIG. 7 (Sheet 5) is an end elevation on the machine shown in FIG. I, on an enlarged scale.

FIG. 8 (Sheet 5) is a sectional elevation on the plane 8-8 of FIG. 5.

FIG. 9 (Sheet 5) is a section elevation of the plane 9-9 of FIG. 5.

FIG. 10 (Sheet 6) is an end view showing the interengagement of a carrier assembly with the guideway rail.

FIG. 11 (Sheet 6) is an exploded view of the components ofa carrier assembly of FIG. 12.

FIG. 12 (Sheet 6) is a bottom view showing the interrelationship ofthe carrier configurations.

programed DESCRIPTION OF THE PREFERRED EMBODIMENT The device illustrated in the drawings has a floorsupport pedestal generally indicated at 10 providing a height adjustment as a result of the telescoping engagement of the inner tube 11 with the outer tube 12. The adjusted position of these tubes is maintained by tightening the set screws 13. A bracket 14 is secured to the inner tube II to act as a mounting point for the principal structure ofa shadow line device generally indicated at 15. The housing 16 functions additionally as a frame, and is provided with a group of tabs 17-20 bolted. to the bracket 14 as shown. A second group of tabs '21-24 at the opposite end of the housing 16 permits the attachment of the floor structure in reverse relationship from that shown in FIG. 1. In such an insion of the housing 16 from the floor support 10. In the I particular modification illustrated in the drawings, the projector assembly 28is in fixed position, and the projector assemblies 26 and 27 are movable in parallel relationship to reflect the corresponding movement of a machine component with which the device is associated.

Thehousing-frame 16 is an elongated rectangular sheet metal structure with an opening in the bottom defined by the flanges 32 and 33. A channel rail 34 is placed within the housing-frame 16 with the flanges 35 and 36 of the rail extending downwardly from the web 37. The outer ends of the flanges 35 and 36 rest on the in-turned flanges 32 and 33 of the frame-housing 16, and the rail 34 is positioned laterally in an approximate location by small screws 40 and 41 traversing the material of the frame-housing 16. Referring particularly to FIG. 9 (Sheet the rail flanges 35 and 36 are tapered toward increasing thickness adjacent the web 37, and are provided with grooves 42 and 43 machined into the relatively thick material adjacent the web 37. The channel 34 is a conventional structural configuration, and may be either extruded or hot-rolled to the illustrated cross-section. Applicants have found that aluminum is a very effective material for the rail 34, as it not only functions well as a guideway with relatively less weight than other metals, but also serves the addi tional purpose of dissipating heat from the points of concentration adjacent the projector assemblies. The grooves 42 and 43 are machined in the otherwise conventional cross-section of the rail by a standard milling operation, The conventional tapered configuration of the flanges 35 and 36 provides the stiffness associated with the vertical height of these flanges, and yet places the maximum thickness of material at a point where it is best utilized to form the grooves without weakening the flanges. The rail 34, with the grooves 42 and 43 machined in it, constitutes the guideway of the shadow line device supporting the movable projector assemblies 26 and 27. The fixed projector assembly 28 is suspended from the bolts 44 and 45 traversing the plates 46 and 47 extending across the gap between the flanges 32 and 33, clamping these flanges between them under the action ofthe nuts 48-5l.

The movable projector assemblies are supported by the guide rail 34 with the assembly shown in FIGS. 8, l3, and I4 (Sheets 5 and 7). A carrier assembly is formed by the base plate 52, the bolts 53-54, the rollers 55-56 and the concentric bushings 57 and 59, the.

washers 58 and 60, the bolts 61, the rollers 62, the eccentric bushing 63, and the washer 64. The rollers 55, 56, and 62 are preferably standard ball bearings, as shown at 620, with an annular wear shoe or tire as shown at 6212 pressed onto the outer race of the bearing. The bolts 53 and 54 function as fixed shafts supporting the rollers 55 and 56, the threaded ends of the bolts engaging the correspondingly threaded holes 66 and 67 in the base plate 52. The length of the bolts 53-54 and 61 are preferably selected so that they traverse the base plate 52 and project far enough beyond it to receive lock nuts as shown at 69 in FIG. 13. This arrangement permits predetermined space to exist between the heads of the bolts and the base plate 52 to maintain a close but free mounting on the rollers. While the fixed rollers 55 and 56 are mounted in pairs, the single rollers 62 are adjustable toward and away from the associated guideway groove in the rail 34 by the lateral adjustability provided by the eccentric bushing 63. The bolts 61 can be tightened against the ends of the bushings 63 to establish the desired adjustment, with the loosening of the bolts permitting rotation of the eccentric bushing 63 to a sufficient degree to permit installation of the carrier assemblies in the guideway grooves. The three-point suspension of the carrier assemblies in the guideway permits the arrangement shown in FIG. 15, in which the adjacent carrier assemblies 27 and 26 have the base plates 52 arranged in opposite orientation to the guideway to permit the illustrated overlap to exist, thus permitting a closer approach of the projector assemblies to each other, and cutting down the minimum distance between the shadow lines. The central suspension bolts 70 are disposed approximately mid-way between the guideway grooves, and the second suspension bolts 71 between the pairs of rollers 55 and 56. This makes the suspension .bolts 71 of adjacent carrier assemblies placed on opposite sides of the structure.-

The movement of the carriers along the guideway rail 34 is controlled by the cables 72 and 73. The cable 72 is secured to the carrier assembly 26 by the clip 74, and the cable 73 to the carrier 27 by the clip 75. These clips function as clamps through the action of the U- bolts 76 traversing the base plates 52, and engaging the nuts 78-79. The opposite courses of the cables 72 and 73 are disposed on the opposite side of the web 37 of the guide rail 34 from the courses secured to the carrier assemblies. The path of these cables is established by the pulleys 80-83. The actuating cables 84 and 85 (extending from the machine'components whose position is registered by the projection devices) are clipped to the cables 72 and 73 as shown at 86 and 87. Opposite courses of the actuating cables 84 and 85 emerge from the end openings 88 and 89 in the housing 16, and are positioned by the pulleys 90-93. When the relative position of the projector assemblies is initially aligned, primarily by the adjustment of the bolts 70-71 within the elongated openings 94-95 in the plates 52, subsequent relative movement within the guideway will be maintained on a strictly parallel relationship between the shadow lines 29-31. The smoothness of the guideway that is almost inherent in the milled grooves 42 and 43 will result in a minimum tendency to vibrate or oscillate the suspension arms a and b of the projector assemblies. The light sources mounted within the housing c ofthe projector assemblies will also be maintained in a constant position, except for the movement along the guideways.

Each of the projector assemblies is serviced by a flexible electrical conduit as shown at 96-98 to supply the light sources within the housings of the projector assemblies, and also with the flexible hoses 99-101 delivering a supply of ventilating air originating in the blower unit 102. This supply arrangement forms no part of the present invention.

The initial alignment of the projector assemblies with respect to each other is supplemented by the group adjustment of angular relationship made possible by the telescoping relationship between the inner and outer support pedestal tubes 11 and 12, which are locked by the screws '13. When these adjustments have been made, they are maintained relatively free of distortion, due to the fact that the guiderail 34 is resting within the housing 16 free of structural stresses associated with the frame-housing 16. The fastenings securing the guiderail 34 against lateral displacement are of a very light nature, and are placed in such a manner that bending and tortional stresses are not transferred from the housing to the guiderail to any substantial degree. The pulley brackets 102 and 103 (refer to FIG. 4, Sheet 2) are secured preferably to the housing, rather than to the guiderail, thus removing another source of potential stress deflection. This structure is capable of installation in any orientation to the horizontal-even in a position in which the guideway rail is vertical. Many applications are thus made practical that otherwise could not utilize a shadow line device.

We claim:

1. A shadow line projector having a frame, guideway means mounted on said frame, at least one carrier mounted for movement along said guideway means, a light source mounted on said carrier, shadow line suspension means mounted on said carrier, and cable means establishing the position of said carrier along said guideway, wherein the improvement comprises:

a unitary channel-shaped rail having a web and also having parallel side flanges provided with opposite grooves forming said guideway means, said rail being normally secured to said frame and having relatively greater torsional and bending rigidity than said frame, said carrier including plate means interposed between said flanges and having roller means engaging said grooves, said cable means having at least one course disposed between said flanges and secured to said plate means.

2. A device as defined in claim 1, wherein said cable means includes a length of cable having courses disposed on opposite sides of said of said web.

3. A device as defined in claim 2, wherein said rail has flanges tapering in thickness, the maximum thickness thereof being adjacent said web.

4. A device as defined in claim 2, wherein said frame includes a housing having an opening along one side, and having inwardly turned flanges along the edges defining said opening, the edges of said rail flanges normally being received on said housing flanges, and said grooves are disposed on the inside of said rail flanges.

S. A device as defined in claim 1, wherein said carrier has at least one roller engaging the other of said grooves, said other roller being mounted on an eccentric member pivotally secured to said carrier to adjustably position said one roller toward and away from said groove. 

1. A shadow line projector having a frame, guideway means mounted on said frame, at least one carrier mounted for movement along said guideway means, a light source mounted on said carrier, shadow line suspension means mounted on said carrier, and cable means establishing the position of said carrier along said guideway, wherein the improvement comprises: a unitary channel-shaped rail having a web and also havinG parallel side flanges provided with opposite grooves forming said guideway means, said rail being normally secured to said frame and having relatively greater torsional and bending rigidity than said frame, said carrier including plate means interposed between said flanges and having roller means engaging said grooves, said cable means having at least one course disposed between said flanges and secured to said plate means.
 2. A device as defined in claim 1, wherein said cable means includes a length of cable having courses disposed on opposite sides of said of said web.
 3. A device as defined in claim 2, wherein said rail has flanges tapering in thickness, the maximum thickness thereof being adjacent said web.
 4. A device as defined in claim 2, wherein said frame includes a housing having an opening along one side, and having inwardly turned flanges along the edges defining said opening, the edges of said rail flanges normally being received on said housing flanges, and said grooves are disposed on the inside of said rail flanges.
 5. A device as defined in claim 1, wherein said carrier has at least one roller engaging the other of said grooves, said other roller being mounted on an eccentric member pivotally secured to said carrier to adjustably position said one roller toward and away from said groove. 